Objective: To compare random amplified polymorphic DNA (RAPD) analysis and ribotyping with serotyping for epidemiologic typing of Escherichia coli.
Methods: Thirty-two epidemiologically unrelated strains, nine cerebrospinal fluid isolates with the O7K1 serotype from nine patients, and nine sets of epidemiologically related E. coli isolates from nine patients were typed by RAPD analysis, ribotyping and serotyping.
Results: Among the 32 epidemiologically unrelated E. coli isolates, 29 types were distinguished by RAPD analysis, 25 by ribotyping and 27 by serotyping. Indistinguishable patterns were obtained by RAPD analysis and ribotyping within the collection of nine cerebrospinal fluid isolates. For the epidemiologically related isolates, intrapatient variation was only found by RAPD analysis among the isolates of one set and by ribotyping among the isolates of two sets. No interpatient variation was observed between three sets of isolates. With serotyping, the epidemiologically related isolates yielded similar typing relationships to those obtained by RAPD analysis and ribotyping.
Conclusions: RAPD analysis had the highest discriminatory capacity for typing E. coli isolates. RAPD analysis, ribotyping and serotyping can all be used for assessment of strain relationships.